نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
گروه علوم و مهندسی صنایع غذایی، دانشکده کشاورزی، دانشگاه صنعتی اصفهان، اصفهان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: Essential oils are natural volatile compounds derived from plant materials. The application of essential oils in food industry is limited due to their instability, strong flavor and decomposition against environmental and chemical conditions such as light, humidity, oxygen, etc. In recent years, utilization of essential oils as natural additives has been increased in recent years, researchers have proposed encapsulation as a way to increase the stability of essential oils in food systems. The purpose of this study was to prepare microencapsulated mustard essential oil with different ratio of wall materials (gum Arabic (GA): maltodextrin (MD)) using spray dryer.
Materials and Methods: The chemical composition of mustard essential oil was determined by the use of gas chromatography−mass spectrometry (GC-MS). Then, in order to obtain an emulsion with desirable properties, 5 emulsion treatments containing different proportions of gum arabic and maltodextrin (20%w/v) were prepared (GA-MD: 100/0, 75/25, 50/50, 25/75, 0/100), afterward the droplet size, viscosity and stability of emulsions were determined. Prepared emulsions were introduced into spray dryer (inlet and outlet air temperatures of 150 and 68 degrees Celsius respectively and feed rate 2 ml/min) and the properties of the powders (moisture, wettability, density, encapsulation efficiency, loading capacity, color and microstructure) were investigated.
Results: Allyl isothiocyanate (39.88%) was the main component of mustard essential oil. According to the obtained results, utilization of higher concentration of gum arabic directed to the formation of emulsions with smaller droplets, better stability and lower phase separation. The highest moisture content in powders was related to GA-MD100/0 treatment (6.72%) and the lowest was observed in GA-MD25/75 sample (3.17%). In general, reduction of the gum arabic ratio and enhancement of maltodextrin, increased the density of microcapsules (p<0.05). Furthermore, due to the lighter color of maltodextrin the L* value of the powders increased, while a* and b* values reduced (p<0.05). The GA-MD 25/75 sample exhibited the highest encapsulation efficiency (94.72%) and loading capacity (18.92%). The scanning electron microscopic (SEM) images indicated that all of the microcapsules were spherical, but in sample with 25% gum arabic and 75% maltodextrin no wrinkles, cracks or dents were observed compared to the other treatments. Finally, the treatment containing 25% gum arabic and 75% maltodextrin (GA-MD25/75) was selected as the optimal sample.
Conclusion:
The results of the present study showed that different ratios of wall materials can influence on the properties of the prepared emulsions as well as the powders obtained from the spray drying process. Increasing the ratio of gum arabic as a wall material in mustard essential oil emulsions increased the viscosity and stability of emulsions and reduced the size of emulsion droplets. On the other hand, enhancement of maltodextrin ratio, could increase the micoencapsulation efficiency and loading capacity, Therefore and the treatment containing 25% gum arabic and 75% maltodextrin was selected as the optimum treatment with desirable characteristics.
کلیدواژهها [English]
)